Respiratory Effects of Obesity in Children

Childhood Obesity Clinical Trial

Official title:

Respiratory Effects of Obesity in Children

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT03376880
• Other study ID #: STU 052012-076
• Status: Recruiting
• Start date: April 26, 2017
• Est. completion date: June 30, 2025

Study information

• Verified date: November 2023
• Source: University of Texas Southwestern Medical Center
• Contact: Raksa Moran
• Phone: 214-345-6574
• Email: IEEMLung[@]TexasHealth.org
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

In obese children, excess fat on the thorax exerts an unfavorable burden on the respiratory system, particularly during exercise; however, it is unclear if this burden reduces exercise tolerance, provokes dyspnea on exertion, or contributes to respiratory symptoms that could be misdiagnosed as asthma, placing obese children at risk of unnecessary treatment and potentially a reluctance to exercise explaining reports of low physical activity and fitness levels, which are counterproductive to weight loss. The investigators will examine the respiratory effects of obesity in prepubescent boys and girls, including those with respiratory symptoms misdiagnosed as asthma, before and after 1) a program of weight loss and regular exercise and 2) continued weight gain as compared with prepubescent normal weight boys and girls before and after 1 year. These results will have broad and immediate clinical impact on the care of obese children, especially those with respiratory symptoms misdiagnosed as asthma, and the results could alter interventional approaches for preventing and treating childhood obesity.

Description:

In obese children, excess fat exerts an unfavorable burden on the respiratory system, particularly during exercise, potentially reducing exercise tolerance and leading to DOE (dyspnea on exertion), which could explain reports of low physical activity and fitness levels in obese children. The investigators propose that most of the respiratory effects in obese children are the result of low lung volume breathing, i.e., a reduction in functional residual capacity (FRC) at rest, and end-expiratory lung volume (EELV) during exercise.

The overall objective of this application is to investigate the respiratory effects of obesity in prepubescent children, including obese children with respiratory symptoms misdiagnosed as asthma, before and after 1) a program of weight loss and regular exercise and 2) continued weight gain as compared with normal weight children before and after 1 yr. The investigative approach will be to examine respiratory function, exercise tolerance, and dyspnea on exertion (DOE) in prepubescent obese boys and girls, including those misdiagnosed with asthma (i.e., asthma not confirmed by lung function tests), before and after 1) weight loss (or an equivalent reduction in BMI percentile) and regular exercise and 2) continued weight gain (or an increase in BMI percentile) as compared with prepubescent normal weight boys and girls before and after a control period of 1 yr.

Specific Aims: The following hypotheses will be tested in obese children as compared with normal weight children:

Aim 1) Obesity will decrease respiratory function but to a greater extent in obese children misdiagnosed with asthma as evidenced by altered pulmonary function and breathing mechanics at rest; Aim 2) Obesity will decrease exercise tolerance (as evidenced by peak maximum oxygen uptake (VO2) in ml/min/kg, i.e., physical fitness), but not cardiorespiratory fitness (as evidenced by peak VO2 in % of predicted based on ideal body wt), except in obese children misdiagnosed with asthma where both may be reduced during graded cycle ergometry; Aim 3) Obesity will increase DOE but to a greater extent in obese children misdiagnosed with asthma as evidenced by increased ratings of perceived breathlessness during constant load exercise cycling; and Aim 4) Weight loss and regular exercise will improve respiratory function, exercise tolerance, and DOE in obese children, including those misdiagnosed with asthma, while continued weight gain will worsen respiratory function, exercise tolerance, and DOE in obese children, including those misdiagnosed with asthma, as compared with normal weight children before and after 1 yr.

The long-term objective is to investigate the effects of obesity on respiratory function, exercise tolerance, and DOE, examine obesity-related respiratory symptoms misdiagnosed as asthma in obese children, and provide novel results that could alter interventional approaches for preventing obesity and treating obesity in obese children. Thus, these results will have broad and immediate clinical impact on the care of obese children, especially those with respiratory symptoms misdiagnosed as asthma.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 96
• Est. completion date: June 30, 2025
• Est. primary completion date: June 30, 2024
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 8 Years to 12 Years

Eligibility

Inclusion Criteria:

• Otherwise healthy with normal lung function; prepubescent (Tanner equal to or less than 3); age and gender specific BMI > 95th percentile, but less than 150% of the 95th percentile based on the CDC standards or age and gender specific BMI between the 16th and 84th percentile based on the Center for Disease Control (CDC) standards; and ability to perform pulmonary and exercise test accurately.

Exclusion Criteria:

• Children with significant diseases other than obesity or shortness of breath on exertion will be excluded. Subjects participating in regular conditioning-type vigorous exercise two times or more per week will be excluded (i.e., sports training). Children who are non-English speaking will be excluded from the study because the tests performed are very effort dependent, detailed, and require technical communication between the staff and the child.

Related Conditions & MeSH terms

• Childhood Obesity
• Obesity
• Pediatric Obesity

Intervention

Other:
• 1 year follow-up testing
The approach of the study is not in studying the effectiveness of the intervention stimulus, the dose response of diet and exercise, or the rate of weight loss but only the response to 1) weight loss and regular exercise or 2) continued weight gain.

Locations

Country	Name	City	State
United States	Institute for Exercise and Environmental Medicine, UT Southwestern and Texas Health Presbyterian Hospital Dallas	Dallas	Texas

Sponsors (1)

Lead Sponsor	Collaborator
University of Texas Southwestern Medical Center

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Pulmonary Function: Spirometry	Spirometry includes: Forced vital capacity (FVC) (liters), Forced Expiratory Volume in 1 second (FEV1) (liters), FEV1/FVC (% ratio), and peak flow (liters/sec)	Change from Baseline differences between nonobese and obese children at 1 yr
Other	Pulmonary Function: Diffusing Capacity	Diffusing Capacity: Diffusing capacity of lung for carbon monoxide(DLco) (ml/mmHg/min)	Change from Baseline differences between nonobese and obese children at 1 yr
Other	Exercise Tolerance: Work Rate	Associated variables such as work rate (W)	Change from Baseline differences between nonobese and obese children at 1 yr
Other	Exercise Tolerance: Minute Ventilation	Associated variables such as pulmonary ventilation (L/min)	Change from Baseline differences between nonobese and obese children at 1 yr
Other	Exercise Tolerance: Operational Lung Volumes	Associated variables such as operational lung volumes (EELV and EILV as a % of TLC)	Change from Baseline differences between nonobese and obese children at 1 yr
Primary	Pulmonary Function: Lung Volumes	Pulmonary function is comprised of several physiological variables but this study will primarily measure Lung Volume: FRC (liters) and TLC (liters)	Change from Baseline in difference between nonobese and obese children at 1 yr
Primary	Exercise Tolerance - Peak VO2	Exercise Tolerances is represented by several physiological variables but the primary variable is Maximal oxygen uptake (L/min and percent predicted)	Change from Baseline differences between nonobese and obese children at 1 yr
Primary	Dyspnea on Exertion	Dyspnea on Exertion is represented using the Borg Scale which provides Ratings of Perceived Breathlessness (RPB) during constant load exercise cycling. The Borg Scale measures from 0-10, where 0 = no breathlessness and 10 = maximal breathlessness.	Change from Baseline differences between nonobese and obese children at 1 yr